Induction and scale-up of Billbergia zebrina nodule cluster cultures: Implications for mass propagation,improvement and conservation

The Tropical Atlantic Rain Forest is a biome of high diversity and endemism of plant genetic resources. High diversity of bromeliad species occurs in this biome, but part of them is now endangered. Tissue culture based techniques comprise valuable tools for the mass propagation and conservation of endangered bromeliads. In the present work the in vitro regenerative system based on the induction and development of NC from nodal segments of Billbergia zebrina showed different morphogenetic features from those observed in organogenesis and somatic embryogenesis. Different levels of TDZ, NAA, and 2i-P promoted the induction of NC with different morphologies and regenerative potential. NC induced in response to 0.01 μM of TDZ and subcultured on BM free of PGR resulted in high regenerative frequency. NC originated from BM supplemented with TDZ (0.1 μM) when subcultured on BM with NAA (2 μM) and 2-iP (4 μM) resulted in higher mean number of shoots. Elongated shoots were successfully acclimatized in ex vitro conditions and derived plantlets had normal phenotype. Histological analyses revealed the morphogenesis of the NC related to organization of the meristematic zone in the subepidermic region composed by organized layers with small and isodyametric cells followed by the induction of shoot buds. SEM analysis showed that the induction of NC occurred from the basal region of the explants.     

Development of expression vectors based on pepino mosaic virus

Background  

Plant viruses are useful expression vectors because they can mount systemic infections allowing large amounts of recombinant protein to be produced rapidly in differentiated plant tissues. Pepino mosaic virus (PepMV) (genus Potexvirus, family Flexiviridae), a widespread plant virus, is a promising candidate expression vector for plants because of its high level of accumulation in its hosts and the absence of severe infection symptoms. We report here the construction of a stable and efficient expression vector for plants based on PepMV.     

The concept of effective population size loses its meaning in the context of optimal management of diversity using molecular markers

Effective population size is a key parameter in conservation genetics. In the management of conservation programs using pedigree information, there is a consensus that the optimal method for maximizing effective population size is to calculate the contribution of each potential parent (the number of offspring that each individual leaves to the next generation) by minimizing the global pedigree-based coancestry between potential parents weighted by their contributions. When using molecular data, the optimal method for managing genetic diversity will remain the same but now the molecular coancestry calculated from markers will replace the pedigree-based coancestry. However, in this situation, the concept of effective population size loses its meaning because with optimal molecular management, genetic diversity increases in early generations and therefore effective population size takes negative values. Furthermore, in the long term, the molecular effective population size does not attain an asymptotic value but it shows an unpredictable behaviour.     

Genome-wide identification of runs of homozygosity islands in the Gyr breed (Bos indicus)

Runs of homozygosity (ROH) are contiguous homozygous regions of the genome. These regions can be used to identify genes associated with traits of economic interest, as well as inbreeding levels. The aim of the present study was to analyse the length and distribution of ROH islands in Gyr cattle and to identify genes within these regions. A population of 173 animals selected for beef production and a population of 291 animals selected for dairy production were used. Differences in the number of short ROH (ROH_{1-2 Mb}) were observed between the two populations, while the number of long ROH (ROH_{>16 Mb}) was similar. ROH islands with the highest incidences (>0.50) overlapped in several segments of the genome in the two populations. The genes identified were associated with milk production, growth, reproduction, immune response and resistance traits. Our results contribute to the understanding of how selection can shape the distribution of ROH and ROH islands within the same breed when animals are selected for different purposes such as dairy or beef production.     

Development of preliminary economic thresholds for an integrated pest management system for soybeans in Java

Abstract

Two field trials were conducted for the purposes of comparing various soybean pest management schemes and setting preliminary economic thresholds that could be used by farmers as part of an integrated pest management (IPM) programme. Both trials tested the same four treatments: (1) a pest management scheme that followed the type of plan that many farmers in Java use, (2) and (3) two schemes utilizing different economic thresholds set by researchers, and (4) an untreated control. The pest management schemes are compared regarding various aspects, including yield and profitability. In both trials the plans did not differ significantly in profitability; however, in each trial the same threshold scheme had the highest mean values for both yield and profitability. Therefore, a pest control system based on this threshold scheme is recommended, with some refinements in certain threshold levels for specific pest guilds where the trials show refinements to be appropriate. It is advised that farmers use the threshold levels recommended here as starting points, and then make adjustments according to the soybean variety used, abundance of natural enemies present, economic factors, etc.     

Kinetics of Mercury Bioaccumulation in the Polychaete Hediste diversicolor and in the Bivalve Scrobicularia plana, Through a Dietary Exposure Pathway

Mercury bioaccumulation kinetics of two important macrobenthic species, the polychaete Hediste diversicolor and the bivalve Scrobicularia plana, were evaluated following a dietary pathway (i.e. contaminated algae), through a mesocosm laboratory experiment. Both studied species presented a similar model of Hg bioaccumulation kinetics, a linear pattern of accumulation through time being the mercury accumulation in the organisms proportional to the mercury concentration in the food. Mercury bioaccumulation rates were higher in the polychaete H. diversicolor (reaching approximately 0.15 μg g⁻¹ at the end of the experiment) than in the bivalve S. plana (≈0.07 μg g⁻¹), which could be related to their feeding strategies, ingestion rates and assimilation efficiencies. Moreover, the mercury bioaccumulation revealed to be quite a fast process especially for the polychaete, and despite the fact that this species is not an edible organism, it is an important prey item, which can greatly contribute to the transport of contaminants to higher trophic levels. Therefore, the bioaccumulation of mercury by these important macrobenthic species, especially the bivalves, represents a non-negligible risk for humans.     

Griffon vulture mortality at wind farms in southern Spain: Distribution of fatalities and active mitigation measures

Wind is increasingly being used as a renewable energy source around the world. Avian mortality is one of the negative impacts of wind energy and a new technique that reduces avian collision rates is necessary. Using the most frequently-killed species, the griffon vulture (Gyps fulvus), we studied its mortality at 13 wind farms in Tarifa, Cadiz, Spain, before (2006–2007) and after (2008–2009) when selective turbine stopping programs were implemented as a mitigation measure. Ten wind farms (total of 244 turbines) were selectively stopped and three wind farms (total of 52 turbines) were not. We found 221 dead griffon vultures during the entire study and the mortality rate was statistically different per turbine and year among wind farms. During 2006–2007, 135 griffon vultures were found dead and the spatial distribution of mortality was not uniformly distributed among turbines, with very few turbines showing the highest mortality rates. The 10 most dangerous turbines were distributed among six different wind farms. Most of the mortalities were concentrated in October and November matching the migratory period. During 2008–2009, we used a selective stopping program to stop turbines when vultures were observed near them and the griffon vulture mortality rate was reduced by 50% with a consequent reduction in total energy production of by the wind farms by only 0.07% per year. Our results indicate that the use of selective stopping techniques at turbines with the highest mortality rates can help to mitigate the impacts of wind farms on birds with a minimal affect on energy production.     

Unsaturated fatty alcohol derivatives of olive oil phenolic compounds with potential low-density lipoprotein (LDL) antioxidant and antiobesity properties

A new route for the synthesis of fatty alcohol derivatives of hydroxytyrosol and other olive oil phenolic compounds was developed to allow the preparation of unsaturated derivatives. The biological activity of synthesized compounds was evaluated. Most of the compounds presented a significant antioxidant activity on low-density lipoprotein (LDL) particles. The activity of the tested products was significantly influenced by the number and position of unsaturations as well as modifications on the polar head of the synthesized compounds. Some of them presented modulation of food intake in rats and, due to their molecular similarity with CB(1) endogenous ligands, the endocannabinoid system and PPAR-α were also evaluated as potential targets. The pharmacodynamics could not be totally explained by CB(1) and PPAR-α receptor interactions because only two of the four compounds with biological activity showed a CB(1) activity and all of them presented low PPAR-α affinity, not justifying its whole in vivo activity. The hydroxytyrosol linoleylether (7) increased LDL resistance to oxidation with a capacity similar to that of hydroxytyrosol and was the most active in vivo compound with a hypophagic effect comparable to that of oleoylethanolamine. We consider that this compound could be a good lead compound for future drug development in obesity treatments.